Selective Perception, Global Warming, and self delusion
A few weeks ago I was talking with a college student, a daughter of some old friends, who had taken a course from an environmentalist professor who apparently claimed that the world temperature had gone up by seven degrees in the last decade or two--she wasn't sure of the precise numbers. She expressed the view that snowy winters were now a thing of the past, offering the (then current, midwest) warmth as evidence.
Currently, the midwest is caught in a severe ice storm and California, where I live, is unseasonably cold instead of unseasonably warm. I have not, however, heard anyone offering that as evidence that the next ice age is impending, and I doubt that the student has revised her predictions.
Of course, the current weather isn't evidence of global cooling, or at least not significant evidence. Nor was the weather a few weeks ago significant evidence for global warming. But once people believe in global warming, it's easy to take each warm spell as evidence and each cold spell as experimental error.
My point is not that global warming isn't real; so far as I can tell it is. My point is rather that the belief in global warming is not, indeed cannot be, supported by the sort of first hand evidence that most of us have from the weather around us. Last year's U.S. temperatures, according to a news story I saw, were a full two degrees above average, making it by some measure the warmest year recorded. But a difference of two degrees is, for most of us most of the time, simply too small to notice. A seven degree (centigrade or fahrenheit not specified) increase over a decade might be noticeable--but that, of course, is fantasy not fact. Wikipedia gives a figure of .6 degrees centigrade over the course of the 20th century.
In this area as in many others, we are in fact dependent on second hand evidence and our ability to evaluate it. But we like to convince ourselves otherwise.